1. Field of the Invention
The present invention relates to an optical component module capable of moving an optical component to be received in a direction of an optical axis, and a camera module including such an optical component module and an image pickup device.
2. Description of the Related Art
In the related art, a camera module into which an optical component and an image pickup device is assembled in advance is mounted on a compact camera, a digital camera, and the like. The camera module is being highly functionalized such that it is provided with an automatic focusing and zooming mechanism so as to be capable of performing zooming photographing of wide angle and telescoping as well as it can cope with a high number of pixels including millions of pixels.
Generally, a camera module includes an optical system having a plurality of lenses, and a board on which an image pickup device is mounted. In a highly advanced camera module, wide-angle and telescoping photographing is allowed by changing the relative position of lens holders that holds a plurality of lenses.
On the other hand, in order to cope with miniaturizing and slimming of an apparatus, demands for making a camera module compact, slim, and lightweight is being increased. In order to meet this demand, a lens system to be used for an optical system of the camera is made small or a case of the camera is thinned. As a result, problems occur in that processing precision is deficient, or an impact is applied to the camera module when the apparatus has fallen and thereby the camera module is damaged.
For example, there is a lens as a typical optical component. As a lens unit including the lens as an optical component, there is a box-shaped lens unit (for example, see Japanese Unexamined Patent Publication JP-A 2002-14270 (FIG. 1)) in which one opening is provided at the top of the unit, and an optical component, such as a lens is assembled through the opening. In this lens unit, a main body having the opening is formed by plastic molding.
Since the optical component is assembled into the main body, the optical performance of the whole lens unit deteriorates due to deficiency in the processing precision of the main body, whereas the optical efficiency is improved by the high-precision main body. More specifically, a recess that extends in the direction of the optical axis is formed in an intersecting part between walls in the box-shaped lens unit. Since this recess is provided to decrease deformation of the main body, it is estimated that deformation resulting from a difference in cooling speed inside and outside the main body is reduced.
Further, a camera module miniaturized by providing a structure in which a housing that holds lens and becomes a whole base is provided at one end of an optical axis of an optical system, and two adjacent side surfaces and a shaft are erected parallel to the optical axis from housing is also disclosed (for example, see Japanese Unexamined Patent Publication JP-A 2005-195669 (FIG. 4)). That is, in the camera module disclosed in JP-A 2005-195669, in order to miniaturize the module, only a surface on which a front lens is to be mounted and two side surfaces parallel to an optical axis passing through this surface and the center of the lens are formed in the housing. Two shafts are provided adjacent to the side surfaces, and the shafts guide sliding of a lens holder that holds a movable lens.
In the configuration disclosed in JP-A 2002-14270, there is a problem in that optimization for the structure including the width, depth, and shape of the recess is required. Further, there is also a problem in that, when the case is intended to be thinned, the strength of a portion of the recess deteriorates. In addition, a guide shaft that guides so as to move a movable lens group parallel to the optical axis is provided in the vicinity of the recess.
In the configuration disclosed JP-A 2005-195669, although there is no deterioration of the optical performance resulting from deformation of the case, only one side of the shaft is fixed. For this reason, there are problems in that the optical performance may deteriorate, such that, during the sliding of the lens holder, the shaft vibrates or the lens holder is slipped off from the other side of the shaft that is not fixed,